Innervation of the pulp-predentin border zone of the cat following denervation and reinnervation.

Under general anesthesia the inferior alveolar nerves of 8 cats were transected unilaterally and the cut ends reapposed. Two of these animals were, under general anesthesia, perfused with fixative 2 days later and 6 animals 12 or 15 weeks later, and the crowns of the mandibular canine teeth were prepared for ultrastructural examination. The distribution of axons at the pulp-predentin border and in the predentinal tubules was measured on the operated and control sides. In unoperated teeth the innervation at the pulp-predentin border paralleled that in the predentinal tubules being denser more coronally. The axons at the pulp-predentin border had disappeared by 2 days after denervation but had returned by 12 weeks and later with a density and distribution similar to that of the control sides.